Flexible impermeable electrical wiring conduit is typically made of a single helically configured metal wall strip having forward and trailing edges which interlock in a movable fashion. A cord is commonly wound helically between the interlocked convolutions to space them apart. The construction has a corrugated appearance and a copper ground wire is often applied exteriorly within the outer helical indentation. The assembly is made moisture proof by a continuous outer jacket of extruded plastic.
End fittings are screwed into the end portions of the conduit and attached to an electrical box. In use electrical wires are pulled through the conduit and connected to terminals in the box with the conduit serving as protective armour and a ground for the wires.
Such prior art conduit does not have a smooth bore and snagging and abrasion sometimes occur as the wires are pulled through. The design is relatively heavy and not notably flexible. The strip convolutions cannot themselves be depended upon to provide a ground circuit and therefore the extra strand ground wire is needed, which only adds to the cost, weight and rigidity of the assembly.
The principal purpose of the present invention is to provide a lighter, less expensive more flexible electrical conduit which possesses all the required crush strength and grounding ability.